Berlin 2015 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 11: Colloids and Complex Liquids II (joint session CPP/ DY)

DY 11.4: Talk

Monday, March 16, 2015, 15:45–16:00, C 130

Linking intermolecular interactions, microstructure, and macroscopic rheology in protein suspensions — •Alessio Zaccone¹, Miriam Siebenbürger², Henning Winter³, Frank Schreiber⁴, and Matthias Ballauff² — ¹Physics-Department, Technische Universität München — ²Helmholtz-Zentrum Berlin für Materialien und Energie — ³University of Massachusetts Amherst — ⁴Applied Physics, University of Tübingen

We propose a microscopic framework based on nonequilibrium statistical mechanics to connect the microscopic level of colloidal biopolymer self-assembly with the macroscopic rheology of protein gelation. The method is based on the master kinetic equations for the time evolution of the self-assembled cluster size distribution, from which the relaxation time spectrum during the gelation process can be extracted. The relaxation spectrum is a simple stretched-exponential, with a stretching exponent related to the mass fractal dimension of the self-assembling clusters. In the case of thermoreversible gelation, for weak interparticle attractions, the attraction energy is finite and plays the role of the control parameter driving a nonequilibrium phase transition into a nonequilibrium steady-state ( the gel). Our theory is in good agreement with experimental data of different systems published by other authors, for which no theory was available. Further, it allows us to interpret new experimental data on the gelation of BSA which provides a benchmark system to connect the level of coarse-grained protein interactions with the macroscopic oscillatory rheology of the protein suspension.